[ Men's Archives |Women's Archives | Contents | Search | Post | Reply | Next | Previous | Up ]
From: Mike(MKP)
Date: 7/3/2002
Time: 1:49:25 AM
Remote Name: 209.152.123.172
...plus maintains ATP levels and is preventative in disorders of excessive apoptosis.And,if that wasnt enough it also reduces expression of inflammatory cytokines.
Cheap as dirt and very soluble in water.Dissolves easily into 2% minox. """"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
Mutagenesis 2002 Jan;17(1):1-8 Related Articles, Books, LinkOut
Inducible protective processes in animal systems. X. Influence of nicotinamide in methyl methanesulfonate-adapted mouse bone marrow cells.
Guruprasad KP, Vasudev V, Anilkumar MN, Chethan SA.
Department of Zoology, Manasagangotri, University of Mysore, Mysore-570 006, Karnataka State, India.
*The adaptive response is an error-free DNA repair mechanism induced by low levels of physical or chemical agents.*
Cells pre-exposed to such agents are resistant to genetic damage induced by subsequent treatment at a high dose. There are many reports on such adaptive responses. Recently we have shown the existence of adaptive responses in vivo in the grasshopper Poecilocerus pictus and the mouse and in vitro in human lymphocytes. Different enzymes are implicated in this DNA repair pathway. In an attempt to understand the molecular mechanism of the methyl methanesulfonate (MMS)-induced adaptive response, the present investigations have been undertaken employing nicotinamide, an inhibitor of the DNA repair enzyme poly(ADP-ribose) polymerase (PARP). Pre-, inter- and post-treatments with nicotinamide of MMS-treated mouse bone marrow cells were carried out. The results revealed that there is a significant reduction in the frequency of chromosomal aberrations compared with combined treatment, suggesting an enhancement of the adaptive response by nicotinamide. Further, the results of NAD+ assay in the inter-treatment experiment showed that there is no depletion of NAD+. Thus, it can be stated that PARP is not involved in the MMS-induced adaptive response in mouse bone marrow cells.
Publication Types: Review Review, Academic
PMID: 11752227 [PubMed - indexed for MEDLINE] """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" : Mol Pharmacol 2001 Jun;59(6):1497-505 Related Articles, Books, LinkOut
Effect of poly(ADP-ribose) polymerase inhibitors on the ischemia-reperfusion-induced oxidative cell damage and mitochondrial metabolism in Langendorff heart perfusion system.
Halmosi R, Berente Z, Osz E, Toth K, Literati-Nagy P, Sumegi B.
University of Pecs, Department of Biochemistry, Faculty of Medicine, Szigeti ut 12, 7624-Pecs, Hungary.
Ischemia-reperfusion induces reactive oxygen species (ROS) formation, and ROS lead to cardiac dysfunction, in part, via the activation of the nuclear poly(ADP-ribose) polymerase (PARP, called also PARS and ADP-RT). ROS and peroxynitrite induce single-strand DNA break formation and PARP activation, resulting in NAD(+) and ATP depletion, which can lead to cell death. Although protection of cardiac muscle by PARP inhibitors can be explained by their attenuating effect on NAD(+) and ATP depletion, there are data indicating that PARP inhibitors also protect mitochondria from oxidant-induced injury. Studying cardiac energy metabolism in Langendorff heart perfusion system by (31)P NMR, we found that PARP inhibitors (3-aminobenzamide, nicotinamide, BGP-15, and 4-hydroxyquinazoline) improved the recovery of high-energy phosphates (ATP, creatine phosphate) and accelerated the reutilization of inorganic phosphate formed during the ischemic period, showing that PARP inhibitors facilitate the faster and more complete recovery of the energy production. Furthermore, PARP inhibitors significantly decrease the ischemia-reperfusion-induced increase of lipid peroxidation, protein oxidation, single-strand DNA breaks, and the inactivation of respiratory complexes, which indicate a decreased mitochondrial ROS production in the reperfusion period. Surprisingly, PARP inhibitors, but not the chemically similar 3-aminobenzoic acid, prevented the H(2)O(2)-induced inactivation of cytochrome oxidase in isolated heart mitochondria, suggesting the presence of an additional mitochondrial target for PARP inhibitors. Therefore, PARP inhibitors, in addition to their important primary effect of decreasing the activity of nuclear PARP and decreasing NAD(+) and ATP consumption, reduce ischemia-reperfusion-induced endogenous ROS production and protect the respiratory complexes from ROS induced inactivation, providing an additional mechanism by which they can protect heart from oxidative damages.
PMID: 11353811 [PubMed - indexed for MEDLINE] """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" : FASEB J 2001 Jan;15(1):99-107 Related Articles, Books, LinkOut
Purines inhibit poly(ADP-ribose) polymerase activation and modulate oxidant-induced cell death.
Virag L, Szabo C.
Inotek Corporation, Beverly, Massachusetts 01915, USA.
Purines such as adenosine, inosine, and hypoxanthine are known to have potent antiinflammatory effects. These effects generally are believed to be mediated by cell surface adenosine receptors. Here we provide evidence that purines protect against oxidant-induced cell injury by inhibiting the activation of the nuclear enzyme poly(ADP-ribose) polymerase (PARP). Upon binding to broken DNA, PARP cleaves NAD+ into nicotinamide and ADP-ribose and polymerizes the latter on nuclear acceptor proteins such as histones and PARP itself. Overactivation of PARP depletes cellular NAD+ and ATP stores and causes necrotic cell death. We have identified some purines (hypoxanthine, inosine, and adenosine) as potential endogenous PARP inhibitors. We have found that purines (hypoxanthine > inosine > adenosine) dose-dependently inhibited PARP activation in peroxynitrite-treated macrophages and also inhibited the activity of the purified PARP enzyme. Consistently with their PARP inhibitory effects, the purines also protected interferon gamma + endotoxin (IFN/LPS) -stimulated RAW macrophages from the inhibition of mitochondrial respiration and inhibited nitrite production from IFN/LPS-stimulated macrophages. We have selected hypoxanthine as the most potent cytoprotective agent and PARP inhibitor among the three purine compounds, and investigated the mechanism of its cytoprotective effect. We have found that hypoxanthine protects thymocytes from death induced by the cytotoxic oxidant peroxynitrite. In line with the PARP inhibitory effect of purines, hypoxanthine has prevented necrotic cell death while increasing caspase activity and DNA fragmentation. As previously shown with other PARP inhibitors, hypoxanthine acted proximal to mitochondrial alterations as hypoxanthine inhibited the peroxynitrite-induced mitochondrial depolarization and secondary superoxide production. Our data imply that purines may serve as endogenous PARP inhibitors. We propose that, by affecting PARP activation, purines may modulate the pattern of cell death during shock, inflammation, and reperfusion injury.
PMID: 11149897 [PubMed - indexed for MEDLINE]
------------------------------------------------------------------------- Cell Death Differ 2000 Mar;7(3):314-26 Related Articles, Books, LinkOut
The NAD+ precursors, nicotinic acid and nicotinamide protect cells against apoptosis induced by a multiple stress inducer, deoxycholate.
Crowley CL, Payne CM, Bernstein H, Bernstein C, Roe D.
Department of Microbiology and Immunology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA.
The bile salt, sodium deoxycholate (NaDOC), is a natural detergent that promotes digestion of fats. At high physiologic levels, NaDOC activates many stress-response pathways and induces apoptosis in various cell types. NaDOC induces DNA damage and activates poly(ADP-ribose) polymerase (PARP), an enzyme that utilizes NAD+ as a substrate to repair DNA. NaDOC also induces oxidative stress, endoplasmic reticulum (ER) stress and contributes to protein malfolding. The NAD+ precursors, nicotinic acid (NA) and nicotinamide (NAM) were found to protect cells against NaDOC-induced apoptosis. NA and NAM also decreased constitutive levels of both activated NF-kappaB and GRP78, two proteins that respond to oxidative stress. However, the mechanism by which NA and NAM protects cells against apoptosis does not involve a reduction in constitutive levels of oxidative stress. NA or NAM treatment increased the protein levels of glyceraldehyde-3-phosphate dehydrogense (GAPDH), a multi-functional enzyme, in the nucleus and cytoplasm, respectively. NAM did not activate the promoter/response elements of 13 stress response genes nor reduce intracellular non-protein thiols, suggesting that it is non-toxic to cells. NAM thus has promise as a dietary supplement to help prevent disorders involving excessive apoptosis.
PMID: 10745276 [PubMed - indexed for MEDLINE]
-------------------------------------------------------------------------- : Trends Pharmacol Sci 1998 Jul;19(7):287-98 Related Articles, Books, LinkOut
Role of poly(ADP-ribose) synthetase in inflammation and ischaemia-reperfusion.
Szabo C, Dawson VL.
Division of Critical Care, Children's Hospital Medical Center, Cincinnati, OH 45229, USA.
Oxidative and nitrosative stress can trigger DNA strand breakage, which then activates the nuclear enzyme poly(ADP-ribose) synthetase (PARS). This enzyme has also been termed poly(ADP-ribose) polymerase (PARP) or poly(ADP-ribose) transferase (pADPRT).
*Rapid activation of the enzyme depletes the intracellular concentration of its substrate, nicotinamide adenine dinucleotide, thus _slowing the rate of glycolysis_(Mike:dermal papilla are derive their ATP from glycolysis), electron transport and subsequently ATP formation.*
This process can result in cell dysfunction and cell death.
In this article, Csaba Szabo and Valina Dawson overview the impact of pharmacological inhibition or genetic inactivation of PARS on the course of oxidant-induced cell death in vitro, and in inflammation and reperfusion injury in vivo. A major trigger for DNA damage in pathophysiological conditions is peroxynitrite, a cytotoxic oxidant formed by the reaction between the free radicals nitric oxide and superoxide. The pharmacological inhibition of poly(ADP-ribose) synthetase is a novel approach for the experimental therapy of various forms of inflammation and shock, stroke, myocardial and intestinal ischaemia-reperfusion, and diabetes mellitus.
Publication Types:
Site Index |
© Copyright 1997 - 2002 TSE
Publishing, Inc. All rights reserved.
No part of this website can be reproduced. Contact
info: HairSite@aol.com